fix(ci): deploys

Deployment fails because pip is not correctly installed for mkdocs

.travis.yml

@@ -1,10 +1,12 @@
 sudo: required
+dist: trusty
 stages:
 - lint
 - test
 - deploy
 language: node_js
-node_js: '10'
+node_js: "10"
+python: "3.4"
 cache:
   directories:
   - "~/.npm"
@@ -25,9 +27,10 @@ jobs:
     - git config credential.helper "store --file=.git/credentials"
     - git config --global user.email "bot@formbuilder.online"
     - git config --global user.name "🤖"
-    - sudo apt-get -y install python3-pip python-dev
+    - sudo apt-get updates
+    - sudo apt-get -y install python3-pip
     - sudo pip3 install -U setuptools
-    - sudo pip install mkdocs
+    - sudo pip3 install mkdocs
     - python3 -V
     - pip3 -V
     - mkdocs -V